Lapping machine



Nov. 4, 1941.` Y Y Hv s; ,NDGE 2,261,902

LAPPING MACHINE Filed Oct. 5, 1940 2 Sheets-Sheet 1 vg s2 77 4 n GO 0 0lsv a G' K f 76 'yq es gq 123K 85 Nov. 4, y1941. Y H. s. INDGEl2,251,902

l LAPPING MACHINE Filed Oct. 5, 1940 2 Sheets-Sheet 2 Ottawa,

Patented Nov. 4, 1941 LAPPIN G MACHINE Herbert S. Indge,

tion of Massachusetts Application October 5, 1940, Serial No. 359,921

2 Claims.

The invention relates to lapping machines, and more particularly to alapping machine for lapping the crankpins and bearings of an automotivecrankshaft.

One object of the invention is to provide an improved lap-ping machinefor lapping crankpins, main bearings and the like.' A further object ofthe invention is to provide an improved hydraulically operated, toggleactuated lapping arm. A further object of the invention is to provide animproved lapping arm in which a flexible abrasive lapping element isemployed which is automatically fed after each lapping operation toprovide a fresh abrading surface for the next operation.

A further object of the invention is to provide an automaticallyactuated positive feed for a flexible abrasive lapping element. Anotherobject of the invention is to provide an automatically actuated paperfeeding mechanism including a pair of positively actuated, springpressedfeed rollers which are actuated automatically at the end of each lappingoperation. Other objects will be in part obvious or in part pointed outhereinafter.

The invention accordingly consists in the features of construction,combinations of elements, and arrangements of parts, as will beexemplified in the structure to be hereinafter described, and the scopeof the application of which will be indicated in the following claims.

In the accompanying drawings, in which is shown one of various possibleembodiments of the mechanical features of the invention,

Fig. l is a cross sectional view through a lapping machine, showing theimproved lapping arm together with a diagrammatic illustration of thehydraulic control and actuating system;

Fig,l 2 is a fragmentary side elevation, on an enlarged scale, of alapping arm having the lapping element and parts shown in an openativeposition for a lapping operation;

Fig. 3 is a similar fragmentary side elevation, on an enlarged scale, ofone of the lapping arms, such as shown in Fig. 2, with the lappingelements and supporting parts in an inoperative position;

Fig. 4 is a fragmentary detail view of the lower abrasive paper feedroll, taken approximately on the line 4 4 of Fig. 2;

Fig. 5 is a fragmentary front elevation of the lapping arm shown in Fig.2, taken approximately on the line 5-5, showing the abrasive paper feedroll broken away and. shown in cross section;

Fig. 6 is a fragmentary cross-sectional View, 55

Westboro, Mass., assigner to Norton Company, Worcester,

Mass., a corporataken 'approximately on the line 6 6 of Fig. 2; and

Fig. '7 is a fragmentary detail view, taken approximately on the line 11 of Fig. 2, having parts broken away and shown in section to moreclearly illustrate the'construotion.

A lapping machine has vbeen illustrated in the drawings comprisinga baseI0 which supports a longitudinally reciprocable table H. Table ways areprovided between the base l0 and table Il which in the preferred formare of an anti-friction type substantially the same as shown anddescribed-in -my prior U. S. Patent No. 2,166,009 datedJuly 19, 1939, towhich reference may be had for details of disclosure not 'containedherein. The table II serves as a support for a headstock` l2 and' afootstock (not shown) which serve as a rotatable support for a workpiece I3.

The headstock l2 is preferably driven by an electric motor I5 which ismounted on the base l0. The motor l5` is provided with a multigroovedpulley I6 which is connected by multiple V-belts Il with a multi-groovedpulley I 8 which is operatively connected to rotate the headstockspindle (not shown) in a manner substantially the same as that disclosedin my prior U. S. patent above referred to.

Lapmng arm support It is desirable to provide a movable support for aplurality of lcrankpin and bearing lapping arms so that they may besimultaneously and rapidly moved into an operative or an inoperativeposition, as desired. A pair of spaced supporting arms 20, only one ofwhich has been illustrated in the drawings (Fig. 1), are mounted on arock shaft 2l which is supported in bearings on the rear of the machinebase l0. The arms 20 are provided with horizontally extending portionswhich are connected by two spaced bars 22 and 23 which serve as lslidebars vor ways for supporting a plurality of lapping arms to behereinafter described.

The lapping arm assembly supported by the arms 20 is arranged so that itmay be automatically moved to and from an operative position tofacilitate loading of `crankshafts into the machine and removing themtherefrom after a lapping operation has been completed. In order to movethe entire lapping arm assembly to and from an operative position, afluid pressure mechanism is provided including a fluid pressure cylinder25 which is pivotally connected by means of a stud 26 with the base I0of the machine. A piston 21 is slidably mounted within the cylinder 25and is connected to one end of a piston rod 28. The other end of thepiston rod 28 is connected by a stud 29 with an arm 39 pivotally mountedon a shaft 3| within the base I9. The arm, 38 is provided with a stud 32which is connected to one end of a link 33. The link 33 is connected bya stud 34 with a toggle lever 35. One end of the toggle lever 35 ispivotally lconnected to a `Stud 36 which is fiXedly supported on thebase I of the machine. The other end of the toggle lever 35 is connectedby a stud 31 with a toggle `lever 38. The opposite end of the togglelever 38 is connected by a stud 39 which is carried ybythe lower end ofi an arm 49. The arm 48 is flxedly supported on the rock shaft 2I.

When fluid under pressure is admitted through a pipe 4I into a cylinderchamber 42, the piston 21 is moved downwardly into the positionillustrated in Fig; 1 which serves through the toggle levers 35 and 38to position the arm 49 and the arms 29 in the position illustrated inFig. l. After a lapping operation has been completed, fluid underpressure is admitted through a pipe 43 into a cylinder` chamber 44 tomove the piston 21 upwardly toward the right, which movement shifts thetoggle levers 35 and 38 into the position illustrated in dotted lines35a and 38a, which movement swings the arm 40 into position 49a. Thismovement of the arm 49 serves to rock the shaft 2I to swing the arms 29together with the entire lapping arm assembly in a clockwise direction-to an inoperative position. f

A fluid pressure system is provided for controlling the admission offluid under pressure to the cylinder 25. A motor driven pump 45 withinthe base I9 of the machine draws fluid through a pipe 46 from areservoir 41 within the base I9 and forces fluid under pressure througha pipe 48 to a reverse or control valve 49. The valve 49 is a balancedpiston type valve having a valve stem 50 which is'provided atits outerend with a spool-shaped member I and isconnected by means of a pair ofdiametrically opposed studs or pins 52 mounted on a lower yokeshaped endof a control lever 53. The control lever 53 is pivotally supported bymeans of a stud 54 on a bracket 55 which is xedly supported on the baseI9 of the machine. A plurality of Valve pistons 56, 51 and 58 are formedintegral with the valve stem 50. Fluid under pressure passing throughthe pipe 48 enters a valve' chamber located between the valve pistons 51and 58 and passes outwardly through the pipe 4I into the cylinder`chamber 42 to move the piston 21 downwardly into the position shown inFig. 1 to move the lapping arm assembly into an operative position.During the downward movement of the piston 21, fluid within the cylinderchamber 44 is exhausted through the pipe 43, through a valve chamberlocated between the valve pistons 56 and.51, and out through an exhaustpipe 59 into the reservoir 41.

After a lapping operation has been completed and it is desired to movethe lapping arm assembly to an inoperative position, the manuallyoperable control lever 53 is moved in a counterclockwise direction toshift the valve pistons 56, 51 and 58 so that uid under pressure passingthrough the pipe 48 enters a valve chamber located between thevalve'pistons 56 and 51 and pass-es outwardly through the pipe 43 intothe cylinder chamber 44 to cause an upward movement of the piston 21.This upward movement of the piston 21 shifts the toggle levers 35 and 38together with the arm 40 into the dotted line positions 35a, 38a and 40ato rock the shaft 2I together with the arms 20 and the entire lappingassembly in a clockwise direction into an inoperative position. Duringthis movement, fluid within the cylinder chamber 42 is exhausted throughthe pipe 4I, through the valve chamber located between the valve pistons51 and 58, and passes outwardly through the exhaust pipe 59 into thereservoir 41.

Lapp'ng arms In'order that all of the crankpins and main bearings on thecrankshaft I3 may be simultaneously lapped, a plurality of crankpin andbearing lapping arms are provided which correspond in number with Vthecrankpins and bearings to be lapped. As illustrated, only one of thelapping arms has been shown. For details of arrangement of the pluralityof lapping arms, reference may be had to my prior U. S. Patent 2,166,009above referred to. A side elevation of a lapping arm 69 is shown inFig. 1. The lapping arm 69 aswell as all of the other lapping arms areeach provided with a pair of pivotally mounted lap supporting arms 6Iand 62 which are provided at their operative ends with partiallycylindrical lap supporting blocks or elements 63 and 64, respectively.The arms 6| and 62 are pivotally supported by studs 65 and 66 on thelapping arm- 69. The other ends of the arms 6I and 62 are connected by apair of toggle levers 61 and 6B which are connected together at.theirinner ends by means of the stud 69vwhich slides in elongated slots 10formed in the side plates of the lapping arm 69. When the toggle levers61 and 68 are in a straightline position, as indicated in Fig. 1, thelap supporting members 63 and 64 are maintained in an operative positionto hold the abrasive or lapping elements in operative contact with thework piece I3.

The lap supporting arms 6I and 62 are arranged to be moved toward andaway from an operative position by means of a hydraulically operatedmechanism comprising a uid pressure cylinder 15 which is mounted on theupper end of the lapping arm 69. A piston 16 is slidably mounted withinthe cylinder 15 and is connected to oneend of a piston rod 11. The otherend of the piston rod 11 is connected by means of the link 18 with thestud 69 which is pivotally connected to the toggle levers 61 and 6B,respectively. Itwill be readily apparent from the foregoing disclosurethat When the piston 16 is moved downwardly, that is, toward the left(Fig. l), the piston rod 11 and the connecting link 18 will be movedalso in a downward direction toward the left, which serves to unlock thetoggle levers 61 and 68 and thereby to rock the lap supporting arms 6Iand 62 together with the lap supporting elements 63 and 64 to aninoperative position out of rengagement with the bearings of thecrankshaft I3 to be lapped.

When fluid under pressure is passed through a flexible pipe 19 into acylinder chamber 89, the piston 16 will be moved upwardly to move thetoggle levers 61 and 68 into the position shown in Fig. l to move thelapping element into operative engagement with the work piece I3 for alapping-operation. Similarly, when fluid is admitted through a flexiblepipe 8I into the cylinder 15 to cause a downward movement of the piston16 toward the left (Figs. 1 and 2), the toggle levers 61 and 68 will beunlocked to move the lapping elements to an inoperative position. Eachof the lapping arms 60 is provided with an independent fluid operatedpiston and cylinder mechanism for independently actuating each of thelapping elements.

A pair of longitudinally extending pipes or manifolds 83 and 84 areprovided for supplying fluid under pressure to the flexible pipes 19 and8|, respectively, to a plurality of spaced lapping elements. The lappingarm 60 is pivotally connected by means of a stud 85 which is supportedon a pivotally mounted arm 86. The arm 86 is pivotally supported bymeans of a stud 81 on a supporting member 88. The supporting member 88is in turn adjustably supported on the guide rods 22 and 23,respectively. The supporting member 88 may be adjusted longitudinallyrelative to the rods 22 and 23 to position the arm 60 rin the desiredlocation for lapping a predetermined portion on the work piece.

A flexible abrasive paper or cloth is preferably utilized as a lappingmedium. Each of the lapping arms 60 is provided with a separate strip ofcontinuous abrasive paper or cloth which wraps around the crankpin ormain bearing to be lapped and is held in position thereagainst by thelap supporting members 63 and 64.

A rod 90 is supported by a pair of brackets 9| (only one of which isshown in Fig. 1) and serves as a support for a reel 92 of exibleabrasive paper 93. The abrasive paper 93 passes through guides 94 and 95which are xedly mounted on the under side of the supporting member 88and pass through a series of rollers 96 carried by a bracket 91. Thebracket 91 is in turn supported on the lap supporting arm 62. Theabrasive paper, as above described, wraps around the crankpin I3 and issupported by the lap supporting members 63 and 64.

A manually operable control or reverse valve |05 is provided forcontrolling the admission to and exhaust of fluid from the cylinder 15.Fluid under pressure from the pump 45 passes through a pipe |06 into avalve chamber |01 and in the position illustrated in Fig. 1 passes outthrough a pipe |08, through the manifold 83, and through the flexiblepipe 19, into the cylinder to move the piston 16 upwardly into theposition shown in Figs. 1 and 2. During this movement iiuid within thelower cylinder chamber is eX- hausted through the flexible pipe 8|, themanifold 84, a pipe |09, through a valve chamber IIO and an exhaust pipeIII, into the reservoir 41. When the valve |05 is shifted into a reverseposition, that is, the valve rotor shifted ninety degrees, uid underpressure passing through the pipe |06 will pass through the pipe |09,the manifold 84, the flexible pipe 8|, into the cylinder chamber 82, tocause a downward movement of the piston 16.

The operation of this improved lapping machine will be readily apparentfrom the foregoing disclosure. A work piece I3, such as an automotivecrankshaft, is placed in position for rotation by the headstock I2 andthe footstock (not shown). The work rotation is then started and thecontrol lever 53 is moved in a clockwise direction into the positionshown in Fig. 1 to move the valve pistons so as to 'admit fluid underpressure through the pipe 4| into the cylinder chamber 42 to move thelapping arm assembly supported by the arms 20 into an operativeposition. After the lapping arms have moved to an operative position,the manually operable control -valve |05 is then shifted into theposition illustrated in Fig. 1 so as to admit fluid under pressurethrough the flexible pipe 19 to cause anl upward movement of the piston16, thus moving thev abrasive lapping element into operative lappingengagement with the work piece I3.

. As the lapping operation proceeds, the pressure is increased until thetoggle levers 61 and 68 reach a straight-line position, as indicated inFig. 1, after which the lapping operation' proceeds. After the workpiece has been lapped to the required and predetermined extent, thecontrol valve |05 is shifted into its reverse position to admit fluidunder pressure through the flexible pipe 8| to cause a downward movementof the piston 16 which in turn serves to break the toggle 61-68, therebymoving the lap supporting members 63 and 64 into an open or' inoperativeposition. After the lapping element has been moved to an inoperativeposition, the control lever 53 may then be rocked in a counterclockwisedirection so as to admit fluid under pressure through the pipe 43, intothe cylinder chamber 44, to cause an upward movement of the piston 21which operates through the lever mechanism above described to rock theshaft 2| and the arms 20 to swing the entire lapping arm assembly to aninoperative or loading position, after which the lapped work piece maybe removed from the machine and replaced with a new work piece to belapped. As above explained, the machine may be readily equipped with oneor more of the lapping arms 60 arranged at spaced intervals along theslide bars 22 and 23 in a. manner similar to that shown in my prior U.S. Patent No. 2,166,009 above referred to.

It is desirable to provide a fresh portion of abrasive paper or clothfor each lapping operation in order that a substantially uniform lappingaction may be obtained on successive work pieces. To accomplish thisdesired result, it is desirable to provide an automatic abrasive paperfeeding mechanism which will automatically and positively advance theabrasive paper by an exact and predetermined amount for each lappingoperation. It is desirable to provide a paper feeding ,mechanism whichis arranged automatically and positively to feed the abrasive paper by apredetermined amount each time the lap supporting arms 6I and 62 areopened after a lapping` operation has been The abrasive paper feedingmechanism is supported by a bracket ||5 which is fastened to the lapsupporting element 63 so that it moves to and from an operative positiontherewith. A roller II6 is rotatably supported by a stud II1 adjacent tothe left-hand end of the bracket II5 (Figs. 1, 2 and 3). The peripheryof the roller I I6 is provided with a corrugated or knurled surface II8.A roller II9 is rotatably supported by a stud |20 which is in turnsupported on the left-hand end of a rock arm I2I. The rock arm I2I ispivotally supported on a stud |22 which is fixed relative to the bracket|I5. The periphery of the roller I I 9 is provided with a corrugated orknurled surface |23 which is yieldably urged toward the corrugatedsurface I I8 of the roller ||6 by means of a spring-pressed plunger |24.The compression of the spring-pressed plunger |24 may be adjusted bymeans of a manually adjustable screw I 25 so that a desired pressure maybe exerted between the rollers I|9 and |I6. I

The continuous strip of abrasive paper, which completed.

wraps around the work piece |I3 and engages the lap supporting element63, passes through a guide |26 which is carried by the bracket ||5. Theabrasive paper 93 extends to the left beyond the guide |26 and wraps ina clockwise direction around the knurled peripheral surface ||8 of theroller H6.; Y The abrasive paper then passes through the adjacentknurled surfaces |23 and ||8 of the rollers I|9 and IIB, respectively,and Wraps in a counterclockwise direction around the roller I |9. A gear|28 is xedly mounted on the endA of the roller IIB. The gear |28 mesheswith agear |29 which is, iixedly mounted on the end of the roller |9.

In order to automatically and positively indexv theabrasive lappingelement. 93 by a predetermined amount after each lapping operation, anautomatic indexing mechanism is provided whereby the gea-rs |29 and |28may be readily indexed each time the lap supporting arms 6| and 62- aremoved to an inoperative position.

A holding pawl is provided to at all times hold the gear |29 againstrotation in a clockwise direction. An actuating pawl |31 is pivotallysupported on a stud |38. The stud |38 is in turn supported by a pair ofspaced rock arms |39 and |40 which are pivotally supported on the stud|20. The stud |38 is connected by a rod 4I with a bell crank lever |42.The bell crank lever |42 is pivotally supported by a stud |43. which isfixedly supported in spaced brackets |44 and |45 (Fig. '1). The brackets|44 and |45 are xedly mounted on the lower end of the lapping arm 69.The lower or short arm of the bell crank |42 is connected by a stud |46with a link |41. The link |41 is pivotally connected by a stud |48 witha bracket |49 which is xedly mounted on the lap supporting arm 6 In Fig.2 the lap supporting elements 63 and B4 together with the flexibleabrasive lapping element 93` are shown in an operative position togetherwith the other actuating parts thereof and with the abrasive paperfeeding pawl |31 in a retracted position. When fluid under pressure isadmitted to break the toggle levers 6.1 and 63, the lap supporting arm6| moves in a clockwise direction, which movement is transmitted throughthe link |41 to rock the bell crank lever |42. in a counterclockwisedirection so as to shift the rod |4| toward the left (Fig. 1) to movethe pawl supporting arms |39 and |:4lA in a counterclockwise direction,which movement carries the paper feeding pawl |31 also in acounterclockwise direction to rotate the gears |29 and |28 in acounterclockwise and clockwise direction, respectively, to feed theabrasive forward by an exact and predetermined amount to present aportion of fresh abrasive surface for the next lapping operation. Theindex pawl |31 together with its actuating parts is shown in the indexedposition inl Fig. 3. When the lap supporting elements 33 and 64 togetherwithV their actuating parts are again moved into operative position withthe next work piece to be lapped, the index pawl |31 rides idly over theteeth of the gear |29 to return the pawl |31 to its initial position(Fig. 2). During this movement the holding pawl |35 serves to preventmovement of the gear |29 in a clockwise direction.

The rod |4l is preferably adjustably connected to thebell crank lever|42. The bell crank lever |42' is preferably formed as two spaced parts|42. and |42a (Fig. 7).

|5I. The notch I5 serves as a support for the Thebell crank leversupports. a bracket |59; which is provided with a notch` threaded endofthe rod |4I. A pair of spaced nuts and lock nuts |52' and |53 arearranged on opposite sides of the bracket |50 (Fig. 2). By manipulationof the nuts |52 and |53, the eiective length of the rod |4| may bereadily varied as desired.

It will be readily apparent from the foregoing disclosure that each timethe lap supporting elements 63 and 64 are moved to an inoperativeposition after a lapping operation has been completed, this movementwill be automatically transmitted through the indexing mechanism abovedescribed positivelyr and precisely to index the abrasive paper 93 so asto present a predetermined portion of fresh abrasive for the nextsuccessive lapping operation. By utilizing the pair of corrugated orknurled spring-pressed feed rollers, a positive indexing movement of theflexible abrasive element is assured.

The operation of this improved lapping machine will be readily apparentfrom the foregoing disclosure. A work piece I3, such as an automotivecrankshaft, is placed in position for rotation bythe headstock I2 andthe footstock (not shown). The work rotation is then started and thecontrol lever 53 is moved in a clockwise direction into the positionshown in Fig. l to move the control valve 49 so that iiuid underpressure will pass through the pipe 4'| into the cylinder chamber 42 tocause a downward movement of the piston 21, thus rocking the entirelapping arm assembly supported by the arms 2-0 to an operative position,such as that shown in Fig. 1.l The valve |35 is then shifted into theposition illustrated in Fig. l to move the lap supporting elements. 63.and 64 into an operative position to wrap the flexible abrasive paper orlapping element 93 around the periphery of the surface to be lapped.

The indexing mechanism above described having previously advanced thepaper 93 by a precise andpredetermined amount, the closing of the lapsupporting elements 63 and 641 serves to advance the abrasive paper 93from the supply roller 92. The lapping operation thenproceedsto thedesired and, predetermined extent, after which the valve |95 isy shiftedso as to admit fluid under pressure throughthe flexible pipe 8| to causea downward movement of the piston 16, which movement breaks the togglelevers 61 and 68 and moves the lap, supporting elements 63 and 64 intoan inop erative position away from the work piece I3. During thismovement, the index pawl |31 is automatically moved in acounterclockwise direction to rotate the gear |29 in a counterclockwisedirection and the gear |28 in a clockwise direction, thusA advancing theabrasive paper 93 by a precise and predetermined amount to present apredeterminedl fresh abrasive surface for the next lapping operation. Asabove explained, the machine may be readilyy equipped with one or morelapping arms 30 arranged at spaced intervals along the supporting bars22 and 23 in a manner similar to that shown in my prior U. Si. PatentNo. 2,166,009-above referred to.

It will thus be seen that there has been providedv by this4 inventionapparatus in which the various objects hereinabove set, forth togetherwith many thoroughly practical advantages are successfully achieved. Asmany possible embodiments may be made of the above invention and as manychanges might be made in the embodiment above set forth, it is to beunderstood that all a75. matter hereinbefore. set forth or'shown in the.ac-

oinpanying drawings is to be interpreted as illustrative and not in alimiting sense.

I claim:

1. In a lapping arm for lapping cylindrical work pieces, a exible stripof abrasive to loop around a work piece, a pair of opposed jaws havingsurfaces arranged to clamp said abrasive in abrading contact with aworkpiece, means to move said jaws to and from an operative position,guiding rollers supported by one of said jaws, a pair of opposedrough-surfaced, spring-pressed rotatable feed rollers supported by theother jaw, means to adjust the relative pressure between said rollers,gearing operatively connecting said rollers, means including a pawlengageable with said gearing, and means including adjustable connectionsbetween said pawl and one of said jaws which is actuated by movement ofsaid jaws to an inoperative position automatically to actuate said pawland index said abrasive by a precise and predetermined amount.

2. In a lapping arm for lapping cylindrical work pieces having a exiblestrip of abrasive to loop around a work piece, a pair of pivotallymounted opposed shoes to support the abrasive element in abradingcontact with the work piece, a pair of toggle levers to move said shoesto and from an operative position, and an abrasive element feedingmechanism including an abrasive guiding device supported by one of saidjaws, a pair of opposed rough-surfaced, spring-pressed rotatable feedrollers supported on the other jaw, said abrasive element passingbetween said rollers, gearing operatively connecting said rollers, meansincluding an index pawl engageable with said gearing, means including apivotally mounted lever which is adjustably connected to actuate saidpawl, and operative connections between said lever and one of saidtoggle levers which is actuated automatically by movement of said togglelevers to an inoperative position automatically to actuate said pawl andfeed said abrasive element a precise and predetermined amount.

HERBERT S. INDGE.

